山东荣成成山头“柳夼红层”的层序、划分与成因及其气候意义())

THE SEQUENCE, DIVISION, GENESIS AND CLIMATIC IMPLICATION OF 'LIUKUANG RED BEDS' IN CHENGSHANTOU, RONGCHENG COUNTY,SHANDONG PROVINCE

“柳夼红层”可分两段。上段为一套风成砂层与土壤粘土层相互叠置的旋回性沉积,偏下部夹有冲洪积砂砾层。共发现8个一级界面,可分出9个冷、暖气候旋回,是我国北方沿岸末次冰期的良佳记录。下段为土壤化砂质粘土层,属于末次间冰期的地质记录。“柳夼红层”风成沉积的环境标志明显,三级序次界面清晰,冷、暖环境交替频繁,对末次冰期气候期的划分对比是有意义的。

Liukuang red beds', the red-coloured strata which crop up on the north coast of Chengshntou, Rongcheng county, Shandong Province, bear no fossils. Debate has been continuing since 1960's on the genesis and age, and the sequence of strata has not been established yet. This paper illustrates the sequence and division of 'Liukuang red beds' as well as the marks of palaeoenvironments in which the strata were formed. In addition, discussions are made about the composition and age of the strata. 'Liukuang red beds' may be divided into two members. The upper member largely consists of a succession of cyclic deposits, namely the alternations of eolian deposits and pedogenic clay beds (soils), subordinate alluvial deposits being intercalated within the lower part. There are eight first-order boundary surfaces in the upper member, showing nine cold/warm climate cycles. The upper member, therefore, has a good geological record of the last glacial stage for the north coasts of China. The lower member, belonging to the record of last interglacial stage, is composed of pedogenic sandy clay beds which are distributed on the erosive surfaces of porphyritic granites formed during the Yanshanian stage. In 'Liukuang red beds', the marks of environment for eolian deposits are clear and three orders of boundary surfaces also obvious, explaining the frequent alternations of cold and warm climates. Consequently, the strata are of significance for the division and comparison of climate stages of the last glacial age.